The deployment of the Terminal High Altitude Area Defense (THAAD) in South Korea was expected to be delayed as President Moon Jae-in ordered a legitimate environmental evaluation over the US missile shield installation.

An unnamed South Korean Defense Ministry official was quoted by Yonhap news agency as saying Wednesday that though the massive assessment of an environmental effect would be conducted, the expected evaluation period of a year or so would be shortened significantly.

Yonhap reported that the comments indicated the completion of the evaluation by the end of this year.

However, the official said the assessment would require the hearings for residents living near the THAAD installation site, which would take several months.

President Moon on Monday ordered a probe into who tried to avoid the "green audit" of the THAAD deployment site, or a golf course at Soseong-ri village in Seongju county, North Gyeongsang province.

South Koreans had held candlelit rallies to protest against THAAD since the deployment decision was made last July.

Moon instructed officials to carry out the legitimate assessment of environmental effect, saying priority should be placed on the procedural legitimacy for the THAAD deployment.

According to the presidential Blue House, its preliminary investigation results showed the Defense Ministry offered 328,799 square meters of the golf course to the US Forces Korea (USFK) in the first stage of land provision.

The total land of the golf course is about 700,000 square meters. The remaining land was scheduled to be given to the USFK in the second stage after completing the green audit.

It was aimed at avoiding the massive environmental evaluation. By domestic law, the provision of less than 330,000 square meters does not require the massive green audit, shortening the assessment period.